205/70R17 vs 225/65R17
Going from one to the other changes the overall height by +0.8 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 205/70R17 | 225/65R17 | Change |
|---|---|---|---|
| Overall height | 28.3" | 28.5" | +0.8 % |
| Sidewall | 5.65" | 5.76" | +1.9 % |
| Section width | 205 mm | 225 mm | +9.8 % |
| Circumference | 88.9" | 89.6" | +0.8 % |
| Revs per mile | 713 | 707 | -0.8 % |
| Axle height | 14.15" | 14.26" | +2.8 mm |
| Approved rim width | 5.5–7.5" | 6–8.5" | overlap 6–7.5" |
Both are approved on a rim 6" to 7.5" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 205/70R17. Fit 225/65R17 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.2 mph | +0.2 |
| 50 mph | 50.4 mph | +0.4 |
| 70 mph | 70.5 mph | +0.5 |
| 90 mph | 90.7 mph | +0.7 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,077 on the road, so it under-counts by 77. At a true 70 mph the first turns 831 times a minute, the second 825.